Ever since President Nixon's 1971 declaration of “War on Cancer,” a set of assumptions has dominated cancer treatment for over 40 years. A war on cancer is a powerfully evocative metaphor that is directly responsible for a counterproductive and even potentially dangerous cell-kill treatment paradigm. (Oronsky et al. 2015). The pharmaceutical industry still develops cancer drugs to achieve the maximally tolerated dose (MTD) in an attempt to achieve a maximal and rapid cell killing.
Chemotherapy and radiation are the ultimate stress test for cancer cells, leading to an unintended “survival of the fittest” response. Chemotherapy, designed to wipe out the tumor, may actually have the opposite effect. This is because the chemosensitive cells, which normally keep the chemoresistant forms in check by competing for scarce space and resources, are killed off, while cancerous tumors adapt in Darwinian fashion to their environment and evolve by clonal expansion and genetic diversification.
(Greaves & Maley 2012). The price of this selection pressure is the emergence of acquired resistance and therapeutic failure, making aggressive therapy a self-defeating process.
Accordingly, there is a need for effective methods of treating cancer which do not result in significant toxicities against non-malignant tissues.
Alkylating agents are a set of anticancer compounds. Ureidomustine (also known as BO-1055) is a selective alkylating agent. It is described in U.S. Pat. No. 8,222,297 B2 and has the following structural formula:

Although ureidomustine was previously suggested as an anti-tumor agent for some cancers, there remains a significant need for methods of treating other cancers with this compound.